This invention relates to methods and equipment for ultrasonic treatment such as cleaning inanimate objects and treating animals including humans for purposes of cleaning, hygiene and therapy.
In one class of ultrasonic cleaning and/or treatment, ultrasonic sound is applied to a working fluid by a transducer. The inanimate object or part of the object or part of the animal to be treated is immersed in the working fluid and the transducer transmits vibrations in the ultrasonic range to that animal or object through the working fluid.
In a prior art ultrasonic system of this class, the cleaning tank is made of metal such as stainless steel and an ultrasound generator is epoxy-bonded, bolted or fastened by any other suitable means to a wall. Such prior art ultrasonic systems are most commonly used for cleaning inanimate objects. Stainless steel rather than high percentage carbon steel tanks are employed to effect resistance against chemical corrosion effects which effects are accelerated in the presence of transient cavitation. Cavitation is introduced by large power vibrations resulting in high airborne acoustic noise well over 100 adjusted decibels in a frequency range which is typically between 20 to 60 kilohertz. The applied power is in a range from a few hundred watts to several kilowatts depending on the cleaning application.
In one prior art type of ultrasonic treatment for humans, ultrasonic sound is applied to patients in a range of power levels of from 0 to 5 watts per square centimeter. It is generally used for stiff joints and muscular disorders. Other examples of treatment using ultrasound are provided in U.S. Pat. No. 4,501,151 to Christman, issued Feb. 26, 1985, for ULTRASONIC THERAPY APPLICATOR THAT MEASURES DOSAGE; U.S. Pat. No. 3,499,436 to Balamuth, issued Mar. 10, 1970, for METHOD AND APPARATUS FOR TREATMENT OF ORGANIC STRUCTURES WITH COHERENT ELASTIC ENERGY WAVES; and U.S. Pat. No. 3,867,929 to Joyner, et al., issued Feb. 25, 1975, for ULTRASONIC TREATMENT DEVICE AND METHODS FOR USING THE SAME; and West German Utility model G8714883.8.
The therapeutic treatment described in the prior art has several deficiencies, mainly arising from the failure to use appropriate frequencies and intensities of ultrasound. For example: (1) some frequencies and intensities increase the risk of overheating the underlying tissue of patients; and (2) some are not useable for hygienic purposes because the selected frequency is higher than desirable. Moreover, the prior art literature does not contemplate antiviral, antibacterial or antifungal activity and has not been applied in a manner to accomplish antiviral, antibacterial or antifungal activity in an effective manner.
It is known to clean parts of the body with the aid of ultrasonic waves transmitted through a liquid medium. For example, U.S. Pat. No. 2,970,073 to Prange, issued Jan. 31, 1961, for METHOD FOR ULTRASONIC SURGICAL CLEANING OF HUMAN BODY MEMBERS discloses the use of ultrasonic sound in a range of between 10 to 200 kilocycles per second in a solution of water, germicide and surfactant to cleanse a surgeons hands. This patent recommends powers below 5 watts per square centimeter and frequencies between 15 to 50 kilocycles per second. Still another cleaning apparatus using ultrasound is described in European patent application, publication no. 0049759. This application describes the use of ultrasound and liquid to remove fingernail polish.
In some embodiments of prior art ultrasound cleaning apparatuses, the frequencies are in the megahertz range extending from approximately 1/4 megahertz to 3 megahertz and in others are above 80 kilocycles such as disclosed in U.S. Pat. No. 3,867,929.
Some ultrasonic cleaning devices of this type have a disadvantage in that they are usable only with additives such as germicides in the case of U.S. Pat. No. 2,970,073 and nailpolish remover in the case of U.S. Pat. No. 3,316,922 or Offenlegungsschrift DE3238476 or European design patent G8714883.8.
The treatment of injured soft tissue and bone is known from Dyson, et al. "Induction of Mast Cell Degranulation in Skin by Ultrasound", IEEE Transaction on Ultrasonics, Ferroelectronics and Frequency Control, vol. UFFC 31, n. 2, March 1986, pp. 194-201. However, this information has not been used in an integrated system for bathing and therapy.
Prior art ultrasonic tanks are generally manufactured from stainless steel. Ultrasonic transducers whether they are piezoelectric or magnetostrictive are bonded to the bottom and/or sides of these stainless steel tubs. Stainless steel rather than high percentage carbon steel tubs are employed to effect resistance against chemical corrosion effects, which effects are accelerated in the presence of transient cavitation.
Decoupled transducers have been employed in stainless steel cleaning tanks. For example U.S. Pat. No. 3,301,535 issued to G. G. Brown, entitled "Ultrasonic Washing Machine and Transducer Therefore" discloses the decoupling of transducers with "O" rings that mount magnetostrictive transducers within holes in an ultrasonic cleaning tank for inanimate objects but the problems associated with tank sealing against the egress of the aqueous medium contained within the cleaning tank and the higher incipient manufacturing cost of the decoupled transducer appear to have mandated against their trade usage.
The method disclosed in U.S. Pat. No. 3,301,535, to form a liquid-tight seal between the decoupled transducer and tank, has two disadvantages, which are: (1) the cost of the decoupled transducer construction is inherently higher than a coupled transducer; and (2) the transducer decoupling factor is lowered significantly because the elastomeric vibration isolation medium is compressed to prevent aqueous medium leakage.